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SOLUTIONS & APPLICATIONS

Vacuum technology for chemical

and pharmaceutical processes

Selecting the right vacuum
technology for these processing
applications is often difficult;
here we will outline the three
approaches most often used

Fig. 1- Dolphin liquid ring vacuum pump from Busch

Uli Merkle, Head of Marketing Services,
Busch Dienste GmbH, Germany It is important to seek
consultation from vacuum
“experts and take into account
electing the right vacuum techno-
logy for chemical and pharmaceuti- all important parameters in the
cal processing applications is often process, starting with process
difficult. Firstly, a vacuum system
has to deliver the required pumping conditions, process gases and
S speed at operating pressure and integration into process control,
thus ensure the required pump-down time. Se- through to economic efficiency,
condly, it cannot be sensitive to process gases
and has to meet all requirements when it comes safety and reliability
to CIP (clean-in-place) cleaning and gas recove-
ry. Reliability and economic efficiency also play
a significant role when deciding which vacuum
technology to use. Liquid ring vacuum pumps
Liquid ring vacuum pumps (Fig. 1) are used in
All of the vacuum generation many applications. They are rotating positive di-
technologies have advantages splacement pumps with an impeller that is eccen-
trically placed in a cylindrical housing (Fig. 2). Water
“and disadvantages. There is usually used as the operating fluid. The rotation
is no single ideal solution for all of the impeller creates a liquid ring on the inside
of the housing that seals the spaces between the
applications individual blades. The gas is conveyed in the spa-
ces between the centre, the individual blades and
Here, we will outline the three vacuum technologies the liquid ring. Thanks to the eccentric placement
most often used in chemical and pharmaceutical of the impeller, the volume of these spaces increa-
processing technologies. ses, thus sucking the medium in through the inlet.
• Liquid ring vacuum pumps As the impeller continues to rotate, the volume of
• Dry screw vacuum pumps the spaces is reduced, the medium is compressed
• Oil-lubricated rotary vane vacuum pumps and then discharged again through the discharge.

92 92 Impiantistica Italiana - Settembre-Ottobre 2020